Fuel injection valve for internal combustion engines

Abstract

A fuel injection valve for internal combustion engines includes a valve member, which is axially displaceable in a bore of a valve body and which on its end toward the combustion chamber of the engine has a conical valve sealing face. The conical valve sealing faced cooperates with a conical valve seat face on the closed end of the bore of the valve body toward the combustion chamber. Between the cone angles of the valve sealing face and the valve seat face, a seat angle difference is provided, by which an encompassing seat edge is formed between the valve member and the valve body, and having at least one injection port in the region of the valve seat phase adjoins the seat edge downstream thereof. For a reliable, defined line of contact on the sealing edge formed by the seat edge, the annular gap adjoining the seat edge downstream thereof, between the valve seat face and the valve sealing face of the valve member is enlarged by an encompassing radial recess between the seat edge and the inlet opening of the injection port.

What is claimed and desired to be secured by letters patent of the United States is: 
     
       1. A fuel injection valve for internal combustion engines, having a valve member (5), which is axially displaceable in a bore (1) of a valve body (3) and on an end toward the combustion chamber of the engine has a conical valve sealing face (7), with which the valve sealing face cooperates with a conical valve seat face (9) on the closed end of the bore (1) of the valve body (3) toward the combustion chamber, and between the cone angles of the valve sealing face (7) and the valve seat face (9) a seat angle difference is provided, by which an encompassing seat edge (25) is formed between the valve member (5) and the valve body (3), and having at least one injection port in the region of the valve seat phase (9) adjoining the seat edge (25) downstream thereof, the annular gap adjoining the seat edge (25) downstream thereof, between the valve seat face (9) and the valve sealing face (7) of the valve member (5), is enlarged by an encompassing radial recess (27) between the seat edge (25) and the inlet opening of the injection port (10). 
     
     
       2. A fuel injection valve in accordance with claim 1, in which the encompassing radial recess (27) is provided in the wall of the valve sealing face (7) of the valve member (5). 
     
     
       3. A fuel injection valve in accordance with claim 1, in which the encompassing radial recess (27) is provided in the wall of the valve seat face (9) of the valve body (3). 
     
     
       4. A fuel injection valve in accordance with claim 1, in which the radial recess (27) directly adjoins the seat edge (25). 
     
     
       5. A fuel injection valve in accordance with claim 1, in which when the valve member (5) is contacting the valve seat (9), a lower, downstream-pointing end (29) of the radial recess (27) is spaced apart by a minimum distance (X) from the upper, upstream-pointing end (31) of the inlet opening of the injection port (10), so that an annular gap region with a small gap size remains between the radial recess (27) and the injection port (10). 
     
     
       6. A fuel injection valve in accordance with claim 1, in which the radial recess (27) is embodied as an annular groove. 
     
     
       7. A fuel injection valve in accordance with claim 6, in which the cross-sectional transition formed between the seat edge (25) and the recess (27) is embodied as sharp-edged. 
     
     
       8. A fuel injection valve in accordance with claim 6, in which the cross-sectional transition formed between the seat edge (25) and the recess (27) has a radius. 
     
     
       9. A fuel injection valve in accordance with claim 6, in which the annular-groovelike recess (27) has a curved cross-sectional shape, whose middle maximum spacing (Y) from the opposed wall face is approximately 0.01 to 0.06 mm. 
     
     
       10. A fuel injection valve in accordance with claim 1, in which the seat angle difference (β) formed between the conical valve seat face (9) and the conical valve sealing face (7) on the valve member (5) is a maximum of 5°. 
     
     
       11. A fuel injection valve in accordance with claim 1, in which the valve member (5) upstream of the valve sealing face (7), a conical inflow face (23) is provided, whose cone angle is smaller than the cone angle of the conical valve sealing face (7), and at the transition between the inflow face (23) and the valve sealing face (7) the seat edge (25) is formed on the valve member (5), and that the inflow angle (α) between the inflow face (23) of the valve member (5) and the valve seat face (9) on the valve body (3) has a size of from 45° to 60°. 
     
     
       12. A fuel injection valve in accordance with claim 1, in which the restoring force that presses the valve member (5) against the valve seat (9) is generated by two valve springs, of which a first valve spring (15) acts constantly upon the valve member (5), and a second valve spring does not engage the valve member (5) until after a preliminary stroke motion of the valve member (5) in the opening direction has been traversed.